I've been using Internet Explorer for years. Why IE? Well, like most people who use IE, it's probably habit more than anything else. It installs with XP so it's pretty easy to just use what's there.
Anyway, a while ago I started having problems with my computer. IE became so unstable that it was unusable. There were other problems too, so I knew a rebuild was on the cards. In the meantime, I decided to install another web browser so I could by until the rebuild.
I installed several web browsers and my favourite was definitely Firefox.
My machine has now been rebuilt and IE is up and running again. However, I was so happy with Firefox that I've decided to continue using it as my primary web browser. Unfortunately, I still have to use IE for some things as not all developers design things to be browser independent. Oh well.